Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

There is provided an interleaved type power factor correction circuit
having a transformer forming a separated winding structure, which is
formed by integrating two inductors separately wound around the
transformer. The interleaved type power factor correction circuit
including a rectifying unit rectifying a commercial alternating current
power, a transformer having a first inductor winding and a second
inductor winding, a bobbin part, and a core part, a switching unit
switching a power transmitted to the first and second inductor windings,
a controlling unit controlling a switching operation of the switching
unit in order to allow a phase difference between a current and a voltage
of the switched power to satisfy a predetermined phase difference, and a
stabilizing unit stabilizing the switched power from the switching unit.

Claims:

1. An interleaved type power factor correction circuit comprising: a
rectifying unit rectifying a commercial alternating current (AC) power; a
transformer including first and second inductor windings individually
receiving the rectified power from the rectifying unit and performing
energy charge and discharge according to a switching operation, a bobbin
part including a bobbin body having a predetermined length, a through
hole penetrating the bobbin body in a lengthwise direction of the bobbin
body, and a winding area provided on an outer circumferential surface of
the bobbin body and having the first and second inductor windings wound
therearound and a partition physically separating the first and second
inductor windings, and a core part including a pair of cores having a
first leg formed by magnetic coupling through the through hole of the
bobbin part and second and third legs formed by magnetic coupling without
passing through the through hole; a switching unit individually switching
the power transmitted to the first and second inductor windings; a
controlling unit controlling the switching operation of the switching
unit in order to allow a phase difference between a current and a voltage
of the switched power to satisfy a predetermined phase difference; and a
stabilizing unit stabilizing the switched power from the switching unit.

2. The interleaved type power factor correction circuit of claim 1,
wherein the first inductor winding and the second inductor winding are
wound in the same direction.

3. The interleaved type power factor correction circuit of claim 1,
wherein the switching unit comprises: a first switch switching the power
transmitted to the first inductor winding, and a second switch switching
the power transmitted to the second inductor winding.

4. The interleaved type power factor correction circuit of claim 1,
wherein the stabilizing unit comprises: a first diode providing a
transmission path of the power transmitted from the first inductor
winding according to the switching operation of the switching unit; a
second diode providing a transmission path of the power transmitted from
the second inductor winding according to the switching operation of the
switching unit; and a capacitor charged with the power transmitted from
the first and second diodes to thereby stabilize the power.

5. The interleaved type power factor correction circuit of claim 4,
wherein the controlling controls the switching operation of the switching
unit depending on a state of the power transmitted from the first and
second diodes to the capacitor.

6. The interleaved type power factor correction circuit of claim 1,
wherein the pair of cores is an EE core or an EI core.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the priority of Korean Patent Application
No. 10-2010-0077736 filed on Aug. 12, 2010, in the Korean Intellectual
Property Office, the disclosure of which is incorporated herein by
reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a power factor correction circuit,
and more particularly, town interleaved type power factor correction
circuit having a transformer forming a separated winding structure, which
is formed by integrating two inductors separately wound around the
transformer.

[0004] 2. Description of the Related Art

[0005] Recently, as an electronic product has become more personalized and
miniaturized, a power supply device supplying a driving power to the
electronic product has also required miniaturization.

[0006] In general, the power supply device converts a commercial
alternating current (AC) power into the driving power. Accordingly, the
power supply device may employ a power factor correction circuit
correcting a phase difference between the current and voltage of a
rectified power by switching a power which rectifies a commercial AC
power, thereby improving a power factor; and a power converting circuit
converting the power factor-improved power into the driving power.

[0007] That is, since the power supply device is required to be
miniaturized, the power factor correction circuit employed therein also
needs to be miniaturized.

SUMMARY OF THE INVENTION

[0008] An aspect of the present invention provides an interleaved type
power factor correction circuit having a transformer forming a separated
winding structure, which is formed by integrating two inductors
separately wound around the transformer.

[0009] According to an aspect of the present invention, there is provided
an interleaved type power factor correction circuit having a separated
winding structure including: a rectifying unit rectifying a commercial
alternating current (AC) power; a transformer including first and second
inductor windings individually receiving the rectified power from the
rectifying unit and performing energy charge and discharge according to a
switching operation, a bobbin part including a bobbin body having a
predetermined length, a through hole penetrating the bobbin body in a
lengthwise direction of the bobbin body, and a winding area provided on
an outer circumferential surface of the bobbin body and having the first
and second inductor windings wound therearound and a partition physically
separating the first and second inductor windings, and a core part
including a pair of cores having a first leg formed by magnetic coupling
through the through hole of the bobbin part and second and third legs
individually formed by magnetic coupling without passing through the
through hole; a switching unit individually switching the power
transmitted to the first and second inductor windings; a controlling unit
controlling the switching operation of the switching unit in order to
allow a phase difference between a current and a voltage of the switched
power to satisfy a predetermined phase difference; and a stabilizing unit
stabilizing the switched power from the switching unit

[0010] The first inductor winding and the second inductor winding may be
wound in the same direction.

[0011] The switching unit may include a first switch switching the power
transmitted to the first inductor winding, and a second switch switching
the power transmitted to the second inductor winding.

[0012] The stabilizing unit may include a first diode, a second diode, and
a capacitor. Here, the first diode may provide a transmission path of the
power transmitted from the first inductor winding. The second diode may
provide a transmission path of the power transmitted from the second
inductor winding. The capacitor may be charged with the power transmitted
from the first and second diodes to thereby stabilize the power.

[0013] The controlling unit may control the switching operation of the
switching unit depending on a state of the power transmitted from the
first and second diodes to the capacitor.

[0014] The pair of cores may be an EE core or an EI core.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other aspects, features and other advantages of the
present invention will be more clearly understood from the following
detailed description taken in conjunction with the accompanying drawings,
in which:

[0016] FIG. 1 is a schematic diagram of an interleaved type power factor
correction circuit according to an exemplary embodiment of the present
invention;

[0017] FIGS. 2A and 2B are a schematic plan view and a schematic side view
of a transformer adopted in an interleaved type power factor correction
circuit according to an exemplary embodiment of the present invention,
respectively;

[0018] FIG. 3 is a graph of an operation waveform of a transformer
according to an exemplary embodiment of the present invention; and

[0019] FIGS. 4A through 4C show electrical characteristics of an
interleaved type power factor correction circuit according to an
exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] Exemplary embodiments of the present invention will now be
described in detail with reference to the accompanying drawings. The
invention may, however, be embodied in many different forms and should
not be construed as being limited to the embodiments set forth herein.
Rather, these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the invention
to those skilled in the art.

[0021] The present invention will be explained in detail with reference to
the drawings, as below.

[0022] FIG. 1 is a schematic diagram of an interleaved type power factor
correction circuit according to an exemplary embodiment of the present
invention.

[0023] Referring to FIG. 1, an interleaved type power factor correction
circuit 100 according to an exemplary embodiment of the present invention
may include a rectifying unit 110, a transformer 120, a switching unit
130, a controlling unit 140, and a stabilizing unit 150.

[0024] The rectifying unit 110 including a bridge diode and a capacitor
may perform the full wave rectification of a commercial alternating
current (AC) power Vac being inputted thereto, and transmit a rectified
power Vin to the transformer 120.

[0025] The transformer 120 may integrate a first inductor winding L1 and a
second inductor winding L2 into a single transformer structure. The
rectified power from the rectifying unit 110 may be inputted to the first
and second inductor windings L1 and L2. According to the switching
operation of the switching unit 130, the first and second inductor
windings L1 and L2 may charge and discharge the energy of the rectified
power. Amore detailed description concerning the transformer 120 will be
provided later, with reference to FIGS. 2A and 2B.

[0026] The switching unit 130 may switch the power inputted to the first
and second inductor windings L1 and L2, thereby allowing energy charged
in the first and second inductor windings L1 and L2 to be discharged and
transmitted to the stabilizing unit 150.

[0027] Accordingly, the switching unit 130 may include a first switch Q1
and a second switch Q2. Here, the first switch Q1 is electrically
connected to the first inductor winding L1 and discharges the energy
charged in the first inductor winding L1. The second switch Q2 is
electrically connected to the second inductor winding L2 and discharges
the energy charged in the second inductor winding L2.

[0028] The controlling unit 140 controlling the switching operation of the
switching ng unit 130, may control the switching operation of the
switching unit 130 depending on a state of the power transmitted from the
switching unit 130 to the stabilizing unit 150. That is, the controlling
unit 140 may control the switching operations of the first and second
switches Q1 and Q2 of the switching unit 130 in order to allow a phase
difference between the current and the voltage of the switched power to
satisfy a predetermined phase difference. Switching control signals for
controlling the switching operations may be individually transmitted to
first and second switches Q1 and Q2 through resistors R1 and R2.

[0029] The stabilizing unit 150 may stabilize the switched power from the
switching unit 130 and output the stabilized power.

[0030] Accordingly, the stabilizing unit 150 may include a first diode and
a second diode D1 and D2, and a capacitor C. Here, the first diode D1 may
form a transmission path of the power transmitted from the first inductor
winding L1. The second diode D2 may form a transmission path of the power
transmitted from the second inductor winding L2. The capacitor C may be
charged with the power transmitted from the first diode D1 and the second
diode D2, to thereby stabilize the power.

[0031] FIGS. 2A and 2B are a schematic plan view and a schematic side view
of a transformer adopted in an interleaved type power factor correction
circuit according to an exemplary embodiment of the present invention,
respectively.

[0032] Referring to FIGS. 2A and 2B together with FIG. 1, the transformer
120 may include a bobbin part 121 and a core part 122.

[0033] The bobbin unit 121 may include a bobbin body having a
predetermined length. The bobbin body may have a through hole formed
therein a length direction thereof. Winding areas 121a and 121b may be
provided on the outer circumferential surface of the bobbin body in which
the through hole is formed, having the first and second inductor windings
L1 and L2 wound therearound.

[0034] The winding areas 121a and 121b may include a first winding area
121a and a second winding area 121b. The first inductor winding L1 may be
wound around the first winding area 121a, and the second inductor winding
L2 may be wound around the second winding area 121b. A partition 121c may
be formed between the first winding area 121a and the second winding area
121b, in order to physically separate the first inductor winding L1 and
the second inductor winding L2.

[0035] Since the first inductor winding L1 and the second inductor winding
L2 are physically separated from each other, the leakage inductance of
the transformer may be increased. Thus, there may be no need of a
separate inductor to obtain a desired amount of the leakage inductance.

[0036] In other words, the amount of leakage inductance in the transformer
may be determined depending on a degree of coupling between windings.
Here, the first inductor winding L1 and the second inductor winding L2
are physically separated from each other such that the leakage inductance
in the transformer increases.

[0037] As indicated by "A" in FIG. 3, when the first inductor L1 is
charged and the second inductor L2 is discharged, that is, the first
inductor L1 and the second inductor L2 operate conversely, there is no
main inductance generated by the windings. This is due to the fact that
no flux is generated in the core of a transformer when current flows
conversely with respect to two individual coils wound in the same
direction. Accordingly, the main inductance does not occur, and the
leakage inductance remains in the first inductor winding L1 and the
second inductor winding L2, thereby allowing the current to flow as
indicated by "B". In this case, when the leakage inductance is very low
or is not present, the power factor correction circuit may operate
abnormally or may fail to perform a voltage boost operation. Therefore,
in an interleaved type power factor correction circuit of the present
invention, the first inductor winding L1 and the second inductor winding
L2 are physically separated by dividing a winding area, while being
integrated into a single transformer. This contributes to achieving
sufficient leakage inductance to allow the power factor correction
circuit to normally operate.

[0038] In addition, the first inductor winding L1 and the second inductor
winding L2 may be wound in the same direction to obtain the same
electrical effects.

[0039] The core part 122 may include a pair of cores 122a and 122b. The
pair of cores may be an EE core; however may also be an EI core having
the same combined form.

[0040] The pair of cores 122a and 122b may include a first leg Leg1 formed
by magnetic coupling through insertion into the through hole of the
bobbin part, and second and third legs Legg and Leg3 formed by magnetic
coupling without insertion into the through hole.

[0041] FIGS. 4A through 4C show electrical characteristics of an
interleaved type power factor correction circuit according to an
exemplary embodiment of the present invention.

[0042] Referring to FIG. 4A together with FIG. 1, when the voltage level
of the commercial alternating power (AC) Vac to be inputted is changed to
90V, 110V, 220V, and 264V, a power factor is maintained at 0.985, 0.980,
0.922, and 0.897. Thus, it can be seen that harmonic components have a
normal level less than a predetermined level while improved power factor
correction may be seen.

[0043] Referring to FIG. 4B together with FIG. 1, when the voltage level
of the commercial alternating power Vac to be inputted is changed to 90V,
110V, 220V, and 240V, the power factor is maintained at 0.985, C.980,
0.936 and 0.922. Thus, the stabilization of an output waveform as well as
improved power factor correction can be seen.

[0044] Referring to FIG. 4C together with FIG. 1, the interleaved type
power factor correction circuit of the present invention and a general
interleaved type power factor correction circuit having two physically
separated inductors have a power conversion efficiency of 93.9% and a
power conversion efficiency of 94%, respectively. Thus, comparing input
power with output power, it can be seen that the interleaved type power
factor correction circuit of the present invention has almost the same
power conversion efficiency as that of the general interleaved type power
factor correction circuit.

[0045] As aforementioned, according to an exemplary embodiment of present
invention, there is provided an interleaved type power factor correction
circuit in which two physically separated inductors are integrated in a
single transformer structure, while two inductor windings are separately
wound around the transformer, whereby component costs as well as circuit
areas can be reduced, compared to the case in which two inductor are
simply used therein.

[0046] As set forth above, according to exemplary embodiments of the
invention, an interleaved type power factor correction circuit forming a
separated winding structure, which is formed by integrating two inductors
separately wound around the transformer can achieve miniaturization and
the reduction of manufacturing costs.

[0047] While the present invention has been shown and described in
connection with the exemplary embodiments, it will be apparent to those
skilled in the art that modifications and variations can be made without
departing from the spirit and scope of the invention as defined by the
appended claims.